The normal laundry system today includes a washer which employs hot water or cold water, depending upon the materials being washed, and a dryer which tumbles the washed clothes in a stream of hot air. The exhaust from the dryer is normally screened to catch as much lint as possible and then exhausted to the atmosphere. While the heat exhausted from the single cycle of a drying operation is not enormous the sum of many such cycles represents a significant waste of heat, particularly in times when energy saving is an important consideration. In the typical commercial installation where a large number of washers and dryers are avilable for individual use, the total waste of energy is large. There have been previous attempts by laundries to conserve the heat which is normally lost to the atmosphere. In each of U.S. Pat. Nos. 3,050,867 to Friedman and 3,771,238 to Vaughn there are systems for preheating feed water to the water heaters by circulating it through the hot air exhaust from the dryers to recover some portion of heat. In U.S. Pat. No. 3,771,238 the feed water to the water heater circulates through a coil of pipe at the top of each dryer in series where recirculated hot air exhaust is blown across the coil and back into the fire box of the dryer. Such a system functions well and transfers heat efficiently but it requires a considerable amount of expensive piping and plumbing fixtures. In U.S. Pat. No. 3,050,867 the feed water to the water heater circulates in parallel through finned tube coils placed in the hot air exhaust stack of each dryer. This, likewise, is an expensive arrangement in that finned tube coils must be custom made to fit the exhaust stack. It is an object of the present invention to provide an improved system for recovering a substantial amount of the waste heat from a laundry dryer and incorporating it into the feed to the water heater.